A first step in the elucidation of the genetic changes and molecular profiles associated with the development of cancer is the isolation of rare tumor cells from a background of millions of normal cells, or the fractionation of a heterogeneous cell population into subpopulations. To this end we propose a versatile, dielectrophoresis-based cell fractionation and isolation platform that is an outgrowth of NCI IMAT funded studies currently underway at M.D. Anderson Cancer Center (MDACC). The goal of the project is to develop a device capable of separating human cells and presenting them in a familiar slide format appropriate for both cytomorphological analysis, which is still the gold standard for cancer diagnosis and staging, as well as a format that can serve as a front-end for emerging molecular analysis methods. The proposed electrosmear device utilizes a proprietary dielectrophoretic electrode array configuration and frequency scheme to levitate cells. This array is configured so that different cell types adhere to the slide in spatially distinct, characteristic bands, making the device ideal for isolating and grouping rare cells. Under an exclusive license from MDACC, Adeptas Inc. will design the appropriate electrodes and controlling electronics, design the sample chamber to permit an optional magnetophoretic separation component, assemble the device, and perform initial proof of concept tests with test particles. The biologically relevant testing of the device will be conducted at MDACC. Experiments at MDACC will utilize a variety of cultured tumor cell lines, whole blood, and buffy coat samples to demonstrate the ability of the electrosmear to isolate and trap cell subpopulations into characteristic bands based upon their dielectrophoretic properties. Key experiments will involve the isolation of tumor cells from spiked blood cell samples to test the limit of detection of the electrosmear method. The MDACC group will also test electrosmear slide compatibility with traditional cell staining methods, cytomorphological evaluation by both a pathologist and more recent automated slide counting cytometry methods, and molecular analysis methods including MALDI-TOF MS. Successful completion of this Phase I SBIR project should provide a basis for a Phase II application and commercialization of the device, which should be immediately applicable by pathologists and researchers in the life sciences.